Change of the Intestinal Flora in the First Year of Life

The analyzes of the microbiome of 98 babies and their mothers, conducted by Swedish scientists, indicates that the type of birth and breastfeeding significantly influence the composition of the child’s intestinal flora. The microbiome is the entirety of the genetic material of all microorganisms living on and in the human body. In this case, the microbes of the lower intestinal tract were examined by analyzing the genetic material of the stool. Thus, conclusions can be drawn to the microbial composition of the gut.

The scientists took samples of mothers at the time of birth and samples of the infants at the time of birth, after 4 and after 12 months. The aim of the study was to find out how the child’s microbiome developed from the time of birth and what influences the type of birth as well as breastfeeding has on the composition of the intestinal flora. They figured that with increasing age the intestinal microbiome of the infants resemble more and more that of their mothers. The intestinal flora of children who had been born vaginally showed a greater resemblance to microbial colonization of the maternal intestine than in children who were born with Caesarean sections. The microbes of the Caesarean children found at the time of birth suggest that many microbes of the skin and the surrounding environment are transmitted to the child’s intestinal microbiome.

The nutrition of the infant, especially at the end of the nursing phase, proved to be particularly important for the development of the intestinal flora. In infants who were no longer breastfed, bacterial species that typically colonize the adult intestine, such as Roseburia, Clostridium and Anaerostipes, were found. In contrast, Bifidobacterium and Lactobacillus dominated the intestinal microbiota of children as long as they were breastfed. The study also describes how the ability of the child’s intestine to produce amino acids and vitamins develops during the first four months of life. According to the scientists, the maturation of the child’s microbiome can be read in the capacity to metabolize micronutrients.

Read more:

F Bäckhed et al. Dynamics and Stabilization of the Human Gut Microbiome during the First Year of Life. Cell Host Microbe. 2015 May 13;17(5):690-703. Doi: 10.1016/j.chom.2015.04.004. 690–703 (2015), available via https://www.ncbi.nlm.nih.gov/pubmed/25974306